The Encyclopedia of Applied Linguistics is a reference work encompassing the range of research on language-related problems that arise in the real-world contexts where languages are learned and used. Because of the wide range of issues that applied linguists work on, a precise definition of the field is difficult to articulate. In his 2007 Introduction to Applied Linguistics, Davies points out that one might be tempted to conclude that "because language is everywhere, applied linguistics is the science of everything," but such a conclusion would be neither correct nor useful (Davies, 2007, p. 2). If applied linguistics is not the science of everything, how is it defined?